HtmlElement.GotFocus 事件
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
發生於此項目已經收到使用者輸入焦點時。
public:
event System::Windows::Forms::HtmlElementEventHandler ^ GotFocus;public event System.Windows.Forms.HtmlElementEventHandler GotFocus;public event System.Windows.Forms.HtmlElementEventHandler? GotFocus;member this.GotFocus : System.Windows.Forms.HtmlElementEventHandler Public Custom Event GotFocus As HtmlElementEventHandler 事件類型
範例
將下列 HTML 程式碼儲存到檔案中，並將檔案 WebBrowser 載入Windows Forms專案中的 控制項。
<HTML>
<BODY>
<FORM name="form1">
<INPUT type="text" size=20 name="text1">
<INPUT type="text" size=20 name="text2">
<INPUT type="text" size=20 name="text3">
</FORM>
</BODY>
</HTML>
下列程式碼範例會防止定位順序中的下一個專案在前一 INPUT 個元素包含少於五個字元時接收使用者輸入焦點。 此範例會要求先前提及的 HTML 檔案載入至名為 WebBrowser1 的 WebBrowser 控制項實例。
HtmlElement targetFormElement;
private void HandleFormFocus()
{
if (webBrowser1.Document != null)
{
HtmlDocument doc = webBrowser1.Document;
if (doc.Forms.Count > 0)
{
HtmlElement targetForm = doc.Forms[0];
HtmlElementCollection searchCollection = targetForm.All.GetElementsByName("text1");
if (searchCollection.Count == 1)
{
targetFormElement = searchCollection[0];
}
}
}
}
private void TargetFormElement_Focus(Object sender, HtmlElementEventArgs e)
{
HtmlElement textElement = e.FromElement;
String elementText = textElement.GetAttribute("value");
// Check that this value is at least five characters long.
if (elementText.Length < 5)
{
e.ReturnValue = true;
MessageBox.Show("The entry in the current field must be at least five characters long.");
}
}
Dim WithEvents TargetFormElement As HtmlElement
Private Sub HandleFormFocus()
If (WebBrowser1.Document IsNot Nothing) Then
With WebBrowser1.Document
If (.Forms.Count > 0) Then
Dim TargetForm As HtmlElement = .Forms(0)
Dim SearchCollection As HtmlElementCollection = TargetForm.All.GetElementsByName("text1")
If (SearchCollection.Count = 1) Then
TargetFormElement = SearchCollection(0)
End If
End If
End With
End If
End Sub
Private Sub TargetFormElement_Focus(ByVal sender As Object, ByVal e As HtmlElementEventArgs)
Dim TextElement As HtmlElement = e.FromElement
Dim ElementText As String = TextElement.GetAttribute("value")
' Check that this value is at least five characters long.
If (ElementText.Length < 5) Then
e.ReturnValue = True
MessageBox.Show("The entry in the current field must be at least five characters long.")
End If
End Sub
備註
您無法取消此事件的預設行為，也無法防止它反升。 若要從專案中移除焦點，請從 事件內 GotFocus 呼叫 Focus 不同的專案。
